Floatable flexible electric lines have already been used in technology for a long time as for supplying electric power to water reservoir cleaning installations, to dredges and the like. Besides the method of fastening heavy rubber hose lines to pontoons or similar floating bodies, lines are also known that are rendered floatable by central cork cylinders or by central, roped-out or twisted arrangement of several air hoses (German unexamined patent specification No. OS 20 56 469). Through the use of cork cylinders, however, the line becomes relatively rigid, even if, as suggested, only short cork cylinders are provided and between them there are arranged rubber disks (German unexamined patent specification No. OS 20 56 469). The production cost is considerable, not least of all through the use of very different materials. The use of roped or wrapped air tubes is, to be sure, a usable solution, but the production expenditure is still very high, both from the process expenditure and also from the material use.
It is also a known practice to use, instead of tubes, to wrap foamed plastic bands with closed pores about a flexible support cable or to provide longitudinally running slit plastic tubes and to arrange over them a closed-pore hollow-cylindrical foamed outer casing (DE-OS 30 05 615). This construction, too, requires expensive manufacturing arrangements and leads to a slow and therefore uneconomical production of the line.
Underlying the invention is the problem of producing a floatable flexible electric and/or optical line of the type mentioned at the outset, which can be manufactured rapidly, with simple machines and with saving in material.